High-entropy metal/ceramic composite materials for harsh environments

ABSTRACT

Aspects disclosed herein include a high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (HEMA) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (HEC) regions characterized by an HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-part of International Patent Application No. PCT/US2022/022016, filed on Mar. 25, 2022, which claims priority to U.S. Provisional Patent Application No. 63/166,376, filed Mar. 26, 2021, which are each hereby incorporated by reference in its entirety.

BACKGROUND

Materials with excellent mechanical properties at high temperatures are very important for applications that involve harsh environments, such as advanced gas turbines, hypersonic vehicles, and nuclear reactors. For example, the operation temperature of turbine blade material is the main limitation of the efficiency of advanced gas turbines. Currently, Ni-based superalloys are the main candidate materials for these applications. However, the operating temperatures of superalloys are limited by the strength reduction at elevated temperatures. Ceramic materials have much higher melting temperatures and high-temperature strength than metal alloys. Yet, the applications of ceramics are limited by their brittleness.

High-entropy materials (HEMs) are a novel class of materials developed recently based on the concept of entropy stabilization. Unlike traditional materials, HEMs contain multiple metal elements in equal or near-equal concentrations but form a stable single-phase crystal structure due to high configurational entropy. Configurational entropy (S) reaches the maximum when the elements are in equi-atomic ratio. Because the minimization of Gibbs free energy (G=H−TS, where H is enthalpy, S is entropy, and Tis temperature) controls the thermodynamic stability of a material, HEMs with a large S can be more thermodynamically stable at high temperatures. Refractory HEMs, including high-entropy (metal) alloys (HEAs) and high-entropy ceramics (HECs), have gained great attention due to their excellent properties. HEAs have metal elements in equal or near-equal concentrations, resulting in a single-phase lattice structure, such as face-centered cubic (FCC) or body-centered cubic (BCC). HECs are ceramic materials in which multiple metal elements are in equal or near-equal atomic ratios in the cation position while a nonmetal element occupies the anion position. Refractory HEAs show enhanced stability and strength than the traditional alloys, especially at high temperatures above 1000° C. HECs are reported to show higher hardness and strength than conventional ceramics at elevated temperatures above 1500° C. As with traditional materials, however, HEAs have high fracture toughness but reduced strength at high temperatures, while HECs have high strength but are brittle.

There exists a need, thus, for a new material that combines the advantageous properties of both HEAs and HECs.

SUMMARY

Provided herein is a new class of materials, and associated methods, referred to as high-entropy metal/ceramic composite (HEMCC) materials for high temperature applications. HEMCC is a unique and new material that contains HEA phase(s) and HEC phase(s) in its microstructure. The HEMCCs combines the high strength of ceramics and high fracture toughness of metals, which enable them to be materials for applications such as next-generation gas turbines, combustion engines, solar power concentrators, thermal protection systems for hypersonic vehicles, plasma-facing materials in nuclear fusion reactors, and structural materials for gas-cooled fast reactors. HEMCCs survive the operation temperatures over 1000° C. to even 1600° C., for example, and provide high strength and fracture toughness at these temperatures in harsh environments.

Aspects disclosed herein include a high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (HEMA) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (HEC) regions characterized by an HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition.

Aspects disclosed herein include a high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (HEMA) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (HEC) regions characterized by a HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition; wherein each HEMA region is free of the HEC material and each HEC region is free of the HEMA.

Aspects disclosed herein include a high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (HEMA) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (HEC) regions characterized by a HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition; wherein each HEMA region is free of the HEC material and each HEC region is free of the HEMA; and wherein at least one HEMA region (or at least one crystallite thereof) is contiguous with at least one HEC region (or at least one crystallite thereof).

Aspects disclosed herein include a high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (HEMA) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (HEC) regions characterized by a HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition; wherein each HEMA region is free of the high-entropy ceramic material and each HEC region is free of the high-entropy metallic alloy; wherein at least one HEMA region (or at least one crystallite thereof) is contiguous with at least one HEC region (or at least one crystallite thereof); and wherein the one or more HEMA regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material and/or the one or more HEC regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material.

Optionally, in any embodiment of a HEMCC material disclosed herein, each HEMA region comprises one or more crystallites characterized by the HEMA composition, or each HEMA region is independently a crystallite characterized by the HEMA composition. Optionally, in any embodiment of a HEMCC material disclosed herein, each HEC region comprises one or more crystallites characterized by the HEC composition, or each HEC region is independently a crystallite characterized by the HEC composition. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC materials comprise two or more HEMA regions and two or more HEC regions; wherein each HEMA region is independently a crystallite characterized by the HEMA composition and each HEC region is independently a crystallite characterized by the HEC composition. Optionally, in any embodiment of a HEMCC material disclosed herein, each HEMA region and each HEC region independently has a homogeneous composition.

Optionally, in any embodiment of a HEMCC material disclosed herein, at least vol. %, optionally at least 95 vol. %, optionally at least 99 vol. %, of each HEMA region and of each HEC region independently has a homogeneous composition. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are greater than 0 vol. %, and less than or equal to 90 vol. % of the HEMCC material, and the one or more HEC regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are 10 vol. % to 90 vol. %, optionally 20 vol. % to 80 vol. %, optionally 30 vol. % to 70 vol. %, optionally 40 vol. % to 60 vol. %, optionally 45 vol. % to 55 vol. %, optionally 48 vol. % to 52 vol. %, of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEC regions are 10 vol. % to 90 vol. %, optionally 20 vol. % to 80 vol. %, optionally 30 vol. % to 70 vol. %, optionally 40 vol. % to 60 vol. %, optionally 45 vol. % to 55 vol. %, optionally 48 vol. % to 52 vol. %, of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the sum volume percent of the one or more HEMA regions and the one or more HEC regions is selected from the range 90 vol. % to 100 vol. %, optionally 95 vol. % to 100 vol. %. Though a HEMCC material optionally, but not necessarily, may comprise one or more amorphous regions, each HEMA region disclosed herein is preferably, but not necessarily, free of an amorphous phase having the respective HEMA composition. Though a HEMCC material optionally, but not necessarily, may comprise one or more amorphous regions, each HEC region disclosed herein is preferably, but not necessarily, free of an amorphous phase having the respective HEC composition. Preferably, the one or more HEMA regions are phase separate from the one or more HEC regions.

Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are greater than 0 wt. %, and less than or equal to 90 wt. % of the HEMCC material and/or the one or more HEC regions are greater than 0 wt. % and less than or equal to 90 wt. % of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, at least 90 wt. %, optionally at least 95 wt. %, optionally at least 99 wt. %, of each HEMA region and of each HEC region independently has a homogeneous composition. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are greater than 0 wt. % and less than or equal to 90 wt. % of the HEMCC material and the one or more HEC regions are greater than 0 wt. % and less than or equal to 90 wt. % of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are 10 wt. % to 90 wt. %, optionally 20 wt. % to 80 wt. %, optionally 30 wt. % to 70 wt. %, optionally 40 wt. % to 60 wt. %, optionally 45 wt. % to 55 wt. %, optionally 48 wt. % to 52 wt. %, of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEC regions are 10 wt. % to 90 wt. %, optionally 20 wt. % to 80 wt. %, optionally 30 wt. % to 70 wt. %, optionally 40 wt. % to 60 wt. %, optionally 45 wt. % to 55 wt. %, optionally 48 wt. % to 52 wt. %, of the HEMCC material. Optionally, in any embodiment of a HEMCC material disclosed herein, the sum volume percent of the one or more HEMA regions and the one or more HEC regions is selected from the range 90 wt. % to 100 wt. %, optionally 95 wt. % to 100 wt. %.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material comprises one or more additives. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more additives of a HEMCC material are less than or equal to 10 vol. %, optionally less than or equal to 5 vol. %, optionally less than or equal to 10 at. %, optionally less than or equal to 5 at. %, of the HEMCC material. The one or more additives may be included to improve the density and mechanical properties of the HEMCC. Optional, non-exhaustive, examples of additives include B₄C, MoSi₂, and carbon fiber. Optionally, the one or more additives of a HEMCC material may be included in one or more of the one or more HEMA regions, in one or more of the one or more HEC regions, and/or separate from the one or more HEMA and the one or more HEC regions.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX1Ab: M_(m1) ¹M_(m2) ²M_(m3) ³M_(m4) ⁴ . . . M_(mi) ^(i) (FX1Ab); wherein: Σ₁ ^(n)m_(i)=1, i is an integer selected from the range of 1 to n; n is an integer selected from the range of 4 to 10; each of M¹, M², M³, and M⁴ and each M^(i), if present, is one of a metal element, preferably a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(i), if present, is a different metal element, preferably refractory metal element, from each other of M¹, M², M³, M⁴, and each M^(i); each mi is independently a relative composition of its respective metal element, preferably refractory metal element, each mi independently being equal to or within 10% (optionally, within 5%) of 1/n; and the sum of each and every mi is 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX1Bb, FX1Cb, FX1Db, FX1Eb, or FX1Fb: M_(a1) ¹M_(a2) ²M_(a3) ³M_(a4) ⁴ (FX1Bb); M_(b1) ¹M_(b2) ²M_(b3) ³M_(b4) ⁴M_(b5) ⁵ (FX1Cb); M_(c1) ¹M_(c2) ²M_(c3) ³M_(c4) ⁴M_(c5) ⁵M_(c6) ⁶ (FX1Db); M_(d1) ¹M_(d2) ²M_(d3) ³M_(d4) ⁴M_(d5) ⁵M_(d6) ⁶M_(d7) ⁷ (FX1Eb); or M_(e1) ¹M_(e2) ²M_(e3) ³M_(e4) ⁴M_(e5) ⁵M_(e6) ⁶M_(e7) ⁷M_(e8) ⁸ (FX1Fb); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a metal element, preferably refractory metal element, different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each a is independently a relative composition of its respective metal element, preferably refractory metal element, each a independently is equal to 0.25 or within 10% (optionally, within 5%) of 0.25, and the sum of each and every a is 1; each b is independently a relative composition of its respective metal element, preferably refractory metal element, each b independently is equal to 0.20 or within 10% (optionally, within 5%) of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective metal element, preferably refractory metal element, each c independently is equal to (⅙) or within 10% (optionally, within 5%) of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective metal element, preferably refractory metal element, each d independently is equal to ( 1/7) or within 10% (optionally, within 5%) of ( 1/7), and the sum of each and every d is 1; and each e is independently a relative composition of its respective metal element, preferably refractory metal element, each e independently is equal to 0.125 or within 10% (optionally, within 5%) of 0.125, and the sum of each and every e is 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX2A or FX2B or FX2C: Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2A); or Hf_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2) (FX2B), or Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)Mo_(1/6) (FX2C).

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX1Aa: M_(m) ¹M_(m) ²M_(m) ³M_(m) ⁴Σ_(i=0) ^(n) M_(m) ^(i) (FX1Aa); wherein: i is 0 or an integer selected from the range of 1 to n; n is 0 or an integer selected from the range of 1 to 10; each of M¹, M², M³, and M⁴ and each M^(i), if present, is one of a metal element, preferably a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(i), if present, is a different metal element, preferably refractory metal element, from each other of M¹, M², M³, M⁴ and each M^(i); each m is independently a relative composition of its respective metal element, preferably refractory metal element, each m independently being equal to or within 10% (optionally, within 5%) of

$\frac{1}{\left( {4 + n} \right)};$

and the sum of each and every m is 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX1Ba, FX1Ca, FX1Da, FX1Ea, or FX1Fa: M_(aa) ¹M_(aa) ²M_(aa) ³M_(aa) ⁴ (FX1Ba); M_(b) ¹M_(b) ²M_(b) ³M_(b) ⁴M_(b) ⁵ (FX1Ca); M_(c) ¹M_(c) ²M_(c) ³M_(c) ⁴M_(c) ⁵M_(c) ⁶ (FX1Da); M_(d) ¹M_(d) ²M_(d) ³M_(d) ⁴M_(d) ⁵M_(d) ⁶M_(d) ⁷ (FX1Ea); or M_(e) ¹M_(e) ²M_(e) ³M_(e) ⁴M_(e) ⁵M_(e) ⁶M_(e) ⁷M_(e) ⁸ (FX1Fa); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a metal element, preferably refractory metal element, different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each aa is independently a relative composition of its respective metal element, preferably refractory metal element, each aa independently is equal to 0.25 or within 10% (optionally, within 5%) of 0.25, and the sum of each and every aa is 1; each b is independently a relative composition of its respective metal element, preferably refractory metal element, each b independently is equal to 0.20 or within 10% (optionally, within 5%) of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective metal element, preferably refractory metal element, each c independently is equal to (⅙) or within 10% (optionally, within 5%) of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective metal element, preferably refractory metal element, each d independently is equal to ( 1/7) or within 10% (optionally, within 5%) of ( 1/7), and the sum of each and every d is 1; and each e is independently a relative composition of its respective metal element, preferably refractory metal element, each e independently is equal to 0.125 or within 10% (optionally, within 5%) of 0.125, and the sum of each and every e is 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX2A or FX2B or FX2C: Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2A); or Hf_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2) (FX2B), or Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)Mo_(1/6) (FX2C).

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMA composition is characterized by formula FX2A, FX2B, FX2C FX2D, FX2E, FX2F, FX2G, FX2H, FX2I, FX2J, FX2K, FX2L, or FX2M: i_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2A); Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2B); o_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2C); W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25) (FX2D); Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25) (FX2E); Hf_(0.2)Zr_(0.2)Ti_(0.2)N₁D_(0.2)Ta_(0.2) (FX2F); Mo_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2) (FX2G); Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2) (FX2H); W_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2) (FX2I); Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)W_(1/6) (FX2J); Mo_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)W_(1/6) (FX2K); Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)Mo_(1/6) (FX2L); Hf_(1/7)Zr_(1/7)Ti_(1/7)Nb_(1/7)Ta_(1/7)Mo_(1/7)N_(1/7) (FX2M).

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3A: (M)_(k)(A)_(p) (FX3A); wherein: each M is four or more metal elements, preferably refractory metal elements; A is one or more nonmetal elements; and each of k and p is independently 1, 2, 3, 4, or 5 (e.g., M₂A, MA₂, MA₃, M₂A₃, MA₄, M₂A₅, etc.). Optionally, in any embodiment of a HEMCC material disclosed herein, each of k and p is independently 1, 2, 3, 4, or 5. Optionally, in any embodiment of a HEMCC material disclosed herein, each of k and p is independently 1 or 2. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3Bb: (M_(r1) ¹M_(r2) ²M_(r3) ³M_(r4) ⁴ . . . M_(rj) ^(j))_(k)(A)_(p) (FX3Bb); wherein: Σ₁ ^(u)r_(j)=1, j is an integer selected from the range of 1 to u; u is an integer selected from the range of 4 to 10; each of M¹, M², M³, and M⁴ and each M_(j), if present, is one of a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(j), if present, is a different metal element, preferably refractory metal element, from each other of M¹, M², M³, M⁴ and each M^(j); each rj is independently a relative composition of its respective metal element, preferably refractory metal element, each rj independently is equal to or within 10% (optionally, within 5%) of 1/u, and the sum of each and every rj is 1; each of k and p is independently 1 or 2; and A is one or more nonmetal elements. In embodiments wherein A is two or more nonmetal elements, each of said two or more nonmetal elements independently resides at an anion position of the structure of the respective HEC region or HEC crystallite. Optionally, in any embodiment of a HEMCC material disclosed herein, A is C, B, N, O, or a combination of these. Optionally, in any embodiment of a HEMCC material disclosed herein, A is C, B, N, or C_(x)N_(1-x), wherein x is selected from the range of 0 to 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3Cb, FX3Fb, FX3Eb, FX3Fb, or FX3Gb: (M_(a1) ¹M_(a2) ²M_(a3) ³M_(a4) ⁴)_(1 or 2)A_(1 or 2) (FX3Cb); (M_(b1) ¹M_(b2) ²M_(b3) ³M_(b4) ⁴M_(b5) ⁵)_(1 or 2)A_(1 or 2) (FX3Db); (M_(c1) ¹M_(c2) ²M_(c3) ³M_(c4) ⁴M_(c5) ⁵M_(c6) ⁶)_(1 or 2)A_(1 or 2) (FX3Eb); (M_(d1) ¹M_(d2) ²M_(d3) ³M_(d4) ⁴M_(d5) ⁵M_(d6) ⁶M_(d7) ⁷)_(1 or 2)A_(1 or 2) (FX3Fb); or (M_(e1) ¹M_(e2) ²M_(e3) ³M_(e4) ⁴M_(e5) ⁵M_(e6) ⁶M_(e7) ⁷M_(e8) ⁸)_(1 or 2)A_(1 or 2) (FX3Gb); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a metal element, preferably refractory metal element, different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each a is independently a relative composition of its respective metal element, preferably refractory metal element, each a independently is equal to 0.25 or within 10% (optionally, within 5%) of 0.25, and the sum of each and every a is 1; each b is independently a relative composition of its respective metal element, preferably refractory metal element, each b independently is equal to or within 10% (optionally, within 5%) of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective metal element, preferably refractory metal element, each c independently is equal to (⅙) or within 10% (optionally, within 5%) of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective metal element, preferably refractory metal element, each d independently is equal to ( 1/7) or within 10% (optionally, within 5%) of ( 1/7), and the sum of each and every d is 1; each e is independently a relative composition of its respective metal element, preferably refractory metal element, each e independently is equal to 0.125 or within 10% (optionally, within 5%) of 0.125, and the sum of each and every e is 1; and A is one or more nonmetal elements. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX4A, FX4B, FX4C, FX4D, FX4E, FX4F, FX4G, or FX4H: (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))C (FX4A); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))B₂ (FX4B); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4C); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4D); (Ti_(0.25)Hf_(0.25)Nb_(0.25)Zr_(0.25)) B₂ (FX4E), (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C_(x)N_(1-x)(FX4F); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))O₂ (FX4G); or (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))O₂ (FX4H); wherein x is selected from the range of 0 to 1.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX4A, FX4B, FX4C, FX4D, FX4E, FX4F, FX4G, FX4H, FX4I, FX4J, FX4K, FX4L, FX4M, FX4N, FX4O, FX4P, FX4Q, FX4R, FX4T, FX4U, FX4V, FX4W, FX4X, FX4Y, or FX4Z: (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))C (FX4A); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)W_(0.2))C (FX4B); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Mo_(0.2))C (FX4C); (Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2))C (FX4D); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))B₂(FX4E); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)W_(0.2))B₂(FX4F); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Mo_(0.2))B₂(FX4G); Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2))B₂(FX4H); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4I); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4J); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25))C (FX4K); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4L); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4M); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4N); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4O); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25))N (FX4P); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4Q); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4R); (Ti_(0.25)Hf_(0.25)Nb_(0.25)Zr_(0.25))B₂(FX4SE); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))B₂(FX4T); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25)) B₂(FX4U); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)) B₂ (FX4V); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))B₂(FX4W); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C_(x)N_(1-x) (FX4X); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))₀₂ (FX4Y); or (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))O₂ (FX4Z); wherein x is selected from the range of 0 to 1.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3A: (M)_(k)(A)_(p) (FX3A); wherein: each M is four or more metal elements, preferably refractory metal elements; A is one or more nonmetal elements; and each of k and p is independently 1, 2, 3, or 5. Optionally, in any embodiment of a HEMCC material disclosed herein, each of k and p is independently 1 or 2. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3Ba: (M_(r) ¹M_(r) ²M_(r) ³M_(r) ⁴Σ_(j=0) ^(u)M_(r) ^(j))_(k)(A)_(p) (FX3Ba); wherein: j is 0 or an integer selected from the range of 1 to n; u is 0 or an integer selected from the range of 1 to 10; each of M¹, M², M³, and M⁴ and each M^(j), if present, is one of a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(j), if present, is a different metal element, preferably refractory metal element, from each other of M¹, M², M³, M⁴ and each M^(j); each r is independently a relative composition of its respective metal element, preferably refractory metal element, each r independently is equal to or within 10% (optionally, within 5%) of

$\frac{1}{\left( {4 + u} \right)},$

and the sum of each and every r is 1; each of k and p is independently 1 or 2; and A is one or more nonmetal elements. In embodiments wherein A is two or more nonmetal elements, each of said two or more nonmetal elements independently resides at an anion position of the structure of the respective HEC region or HEC crystallite. Optionally, in any embodiment of a HEMCC material disclosed herein, A is C, B, N, O, or a combination of these. Optionally, in any embodiment of a HEMCC material disclosed herein, A is C, B, N, or C_(x)N_(1-x), wherein x is selected from the range of 0 to 1. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX3Ca, FX3Fa, FX3Ea, FX3Fa, or FX3Ga: (M_(aa) ¹M_(aa) ²M_(aa) ³M_(aa) ⁴)_(1 or 2)A_(1 or 2) (FX3Ca); (M_(b) ¹M_(b) ²M_(b) ³M_(b) ⁴M_(b) ⁵)_(1 or 2)A_(1 or 2) (FX3Da); (M_(c) ¹M_(c) ²M_(c) ³M_(c) ⁴M_(c) ⁵M_(c) ⁶)_(1 or 2)A_(1 or 2) (FX3Ea); (M_(d) ¹M_(d) ²M_(d) ³M_(d) ⁴M_(d) ⁵M_(d) ⁶M_(d) ⁷)_(1 or 2)A_(1 or 2) (FX3Fa); or (M_(e) ¹M_(e) ²M_(e) ³M_(e) ⁴M_(e) ⁵M_(e) ⁶M_(e) ⁷M_(e) ⁸)_(1 or 2)A_(1 or 2) (FX3Ga); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a metal element, preferably refractory metal element, different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each aa is independently a relative composition of its respective metal element, preferably refractory metal element, each aa independently is equal to 0.25 or within 10% (optionally, within 5%) of 0.25, and the sum of each and every aa is 1; each b is independently a relative composition of its respective metal element, preferably refractory metal element, each b independently is equal to 0.20 or within 10% (optionally, within 5%) of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective metal element, preferably refractory metal element, each c independently is equal to (⅙) or within 10% (optionally, within 5%) of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective metal element, preferably refractory metal element, each d independently is equal to ( 1/7) or within 10% (optionally, within 5%) of ( 1/7), and the sum of each and every d is 1; each e is independently a relative composition of its respective metal element, preferably refractory metal element, each e independently is equal to 0.125 or within 10% (optionally, within 5%) of 0.125, and the sum of each and every e is 1; and A is one or more nonmetal elements. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEC composition is characterized by formula FX4A, FX4B, FX4C, FX4D, FX4E, FX4F, FX4G, or FX4H: (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))C (FX4A); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))B₂ (FX4B); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C (FX4C); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N (FX4D); (Ti_(0.25)Hf_(0.25)Nb_(0.25)Zr_(0.25)) B₂ (FX4E), (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C_(x)N_(1-x) (FX4F); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))O₂ (FX4G); or (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))O₂ (FX4H); wherein x is selected from the range of 0 to 1.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is characterized by a relative density being at least 80%, optionally at least 85%, optionally at least 90%, at least 95%, optionally at least 96%, optionally at least 97%, optionally at least 98%, optionally at least 99%. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is characterized by a density selected from the range of 4 g/cm³ to 12 g/cm³, or any value or range therebetween inclusively, at a temperature selected from the range of 25° C. to 2000° C. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is characterized by a Vickers hardness selected from the range of 2 GPa to 40 GPa, or any value or range therebetween inclusively, at a temperature selected from the range of 25-2000° C. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is characterized by a bending strength selected from the range of 100 MPa to 2000 MPa, or any value or range therebetween inclusively, at a temperature selected from the range of 25-2000° C. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is characterized by a fracture toughness selected from the range of 1 MPam^(1/2) to 20 MPam^(1/2), or any value or range therebetween inclusively, at a temperature selected from the range of 25-2000° C.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material comprises a plurality of the HEMA regions and a plurality of the HEC regions, wherein the HEMA regions and/or HEC regions are distributed throughout the HEMCC material.

Preferably, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is self-supporting. Preferably, in any embodiment of a HEMCC material disclosed herein, the HEMCC material is a bulk material. The HEMCC material is not a powder or mixture of discrete powders, for example, but rather a solid and dense material, in and of itself, having a shape not necessarily defined by its container, as would a mixture of powders.

Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material has a total mass selected from the range of greater than 0 g to 100 kg, or any value or range therebetween inclusively, optionally greater than 0 g to 1 kg, optionally selected from the range of 1 g to 10 kg, optionally selected from the range of 1 g to 10 kg, optionally selected from the range of 1 g to 100 kg. Optionally, in any embodiment of a HEMCC material disclosed herein, the HEMCC material has a total volume selected from the range of greater than 0 cm³ to 2000 cm³, or any value or range therebetween inclusively, optionally greater than 0 cm³ to 200 cm³, optionally selected from the range of 0.3 cm³ to 200 cm³, optionally selected from the range of 0.3 cm³ to 2000 cm³. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are characterized by an average crystallite size (e.g., grain size) selected from the range of 10 nm to 200 μm, or any value or range therebetween inclusively, preferably for some applications 50 nm to 200 μm, preferably for some applications 100 nm to 200 μm, 200 nm to 200 μm. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEMA regions are characterized by at least 80% of crystallite sizes being selected from the range of 10 nm to 200 μm, or any value or range therebetween inclusively, preferably for some applications 50 nm to 200 μm. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEC regions are characterized by an average crystallite size (e.g., grain size) selected from the range of 10 nm to 200 μm, or any value or range therebetween inclusively, preferably for some applications 50 nm to 200 μm, preferably for some applications 100 nm to 200 μm, 200 nm to 200 μm. Optionally, in any embodiment of a HEMCC material disclosed herein, the one or more HEC regions are characterized by at least 80% of crystallite sizes being selected from the range of 10 nm to 200 μm, or any value or range therebetween inclusively, preferably for some applications 50 nm to 200 μm.

Aspects disclosed herein also include any device comprising a high-entropy metal/ceramic composite (HEMCC) material according to any one or any combination of embodiments disclosed herein.

Optionally, in any embodiment disclosed herein, the device is a gas turbine component in the power generation and aviation industries, a coating on structural materials or a fuel cladding component in molten salt reactor (MSR), gas cooled fast reactor (GFR) or very-high temperature reactor (VHTR), or a plasma-facing component for use in the first wall or diverter of a Tokamak nuclear fusion reactor.

Aspects disclosed herein also include a method for making a high-entropy metal/ceramic composite (HEMCC) material, the method comprising: mixing one or more metallic precursors and one or more ceramic precursors; wherein: a combined composition of the one or more metallic precursors comprises four or more metal elements; an atomic percent of each of the four or more metal elements in the combined composition of the one or more metallic precursors is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements in the combined composition of the one or more metallic precursors; a combined composition of the one or more ceramic precursors comprises four or more metal elements and one or more nonmetal elements; an atomic percent of each of the four or more metal elements in combined composition of the one or more ceramic precursors is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements in the combined composition of the one or more ceramic precursors; sintering the mixture of one or more metallic precursors and one or more ceramic precursors thereby forming the HEMCC material comprising one or more high-entropy metallic alloy (HEMA) regions and one or more high-entropy ceramic (HEC) regions; wherein the step of sintering is performed under conditions sufficient to form the HEMA from the one or more metallic precursors and the HEC material from the one or more ceramic precursors.

Optionally, in any method disclosed herein, the step of sintering is performed using a technique selected from the group consisting of spark plasma sintering, pressureless sintering, hot pressing, microwave sintering, laser sintering, a technique equivalent to any of these, and any combination of these. Optionally, in any method disclosed herein, each of the one or more HEMA regions is characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEMA composition; and wherein each of the one or more HEC regions is characterized by a HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% (optionally, within 5%) of an atomic percent of each other of the four or more metal elements of the HEC composition; and wherein: each HEMA region is free of the high-entropy ceramic material and each HEC region is free of the high-entropy metallic alloy; at least one HEMA region (or, at least one crystallite thereof) is contiguous with at least one HEC region (or, at least one crystallite thereof); and the one or more HEMA regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material and/or the one or more HEC regions are greater than 0 vol. % and less than or equal to vol. % of the HEMCC material.

Optionally, in any method disclosed herein, the step of mixing comprises milling the one or more metallic powder precursors and one or more ceramic powder precursors. Optionally, the step of milling comprises the step of milling comprises ball milling, rotor milling, bead milling, cutting milling, a technique equivalent to any of these, or any combination of these. Optionally, in any method disclosed herein, the milling is characterized by a speed selected from the range of 100 to 1000 rpm and a duration selected from the range of 0 to 50 hours, optionally 5 hours to 50 hours, or any range therebetween inclusively. Optionally, in any method disclosed herein, the step of sintering is characterized by a sintering temperature selected from the range of 1000 QC to 2500° C., optionally 1500° C. to 2500° C. Optionally, in any method disclosed herein, the step of sintering is performed via spark plasma sintering (SPS) or hot pressing characterized by a pressure selected from the range of 25 to 500 MPa, optionally 25 to 100 MPa, and a duration selected from the range of 1 to 30 minutes, optionally 5 to 30 minutes. Optionally, in any method disclosed herein, the method comprises forming one or more metallic powder precursors and forming one or more ceramic powder precursors. Optionally, in any method disclosed herein, the step of forming the one or more metallic precursors comprises milling powders having a plurality of metals; and wherein the step of forming the one or more ceramic precursors comprises milling powders having a plurality of ceramics.

Optionally, in any method disclosed herein for making a HEMCC material, the resulting HEMCC material is according to any one or any combination of embodiments disclosed herein.

Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of the invention can nonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 : Schematic diagram of the synthesis process of HEMCCs.

FIG. 2 : SEM images of a HEMCC with different volume percentage of the HEA and HEC phases.

FIG. 3 : Density of a HEMCC as a function of HEC volume percentage.

FIG. 4 : Vickers hardness of a HEMCC as a function of HEC volume percentage.

FIG. 5A: Bending strength and (FIG. 5B) fracture toughness of a HEMCC as a function of HEC volume percentage.

FIG. 6 : An illustration of certain features of a method for making an HEMCC material, according to certain embodiments herein.

STATEMENTS REGARDING CHEMICAL COMPOUNDS AND NOMENCLATURE

In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The following definitions are provided to clarify their specific use in the context of the invention.

The terms “HEA” and “HEMA” are used interchangeably herein and are intended to have equivalent meaning. The term HEA is an acronym for “high-entropy alloy” and the term HEMA is an acronym for “high-entropy metallic alloy.” As used herein, an HEA or high-entropy alloy is a metallic alloy of metal elements.

The term “metal element” refers to a metal element of the Periodic Table of Elements, as would be understood by one of skill in the art. The term “transition metal element” refers to a metal element from the category of transition metal elements (preferably an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell) of the Periodic Table of Elements, including lanthanide and actinide elements. The term “refractory metal element” refers to a metal element of the Periodic Table of Elements which have a melting point above 2000° C., high hardness at room temperature, preferably are chemically inert, preferably have a relatively high density, and preferably are stable against creep deformation to very high temperatures. Preferably, and unless otherwise stated, a refractory metal element is an element selected from the group consisting of Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Ru, Rh, Hf, Ta, W, Re, Os, and Ir.

As used herein, a HEMA composition may be written in shorthand as a series of four or more metal elements, such as TiTaNbZr, which is intended to refer to a HEMA composition having those four or more elements in equal or near-equal (within 10%) atomic ratios with respect to the each, such as Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25). In other words, for example, the HEMA composition TiTaNbZr is equivalent to the HEMA composition Ti_(z)Ta_(z)Nb_(z)Zr_(z) where each z is independently selected from the range of 0.225 to 0.275 (i.e., 0.25±10%) and the sum of each and every z is 1, or optionally selected from the range of 0.9 to 1 in the optional case of the HEMA composition further comprising optional minority additives.

Each HEC region corresponds to a particular compositional and structural material phase. For example, HEC region or HEC crystallite having a HEC composition such as (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C has the said HEC composition generally throughout (preferably homogeneously) said HEC region or HEC crystallite, rather than having or being a mixture of binary carbide materials (e.g., not a mixture titanium carbide, tantalum carbide, niobium carbide and zirconium carbide). Each individual HEC composition disclosed herein is a composition a particular individual material, or region thereof, and rather than an average composition of a mixture of distinct materials. Each individual HEMA composition disclosed herein is a composition of a particular individual material, or region thereof, and rather than an average composition of a mixture of distinct materials.

As used here, atomic ratio(s) or atomic concentration(s) described as “near-equal” refers to a variation of up to 10%, optionally up to 5%, in the value of the atomic ratio(s) or atomic concentration(s) from the value corresponding to an equal atomic ratio or concertation.

The term “mill” or “milling” refers a process or technique known in the art as milling, which, for example, may be used to mill powders. Non-exhaustive examples of milling processes or techniques include ball milling, rotor milling, bead milling, cutting milling, and equivalent techniques. Preferably, but not necessarily, milling refers to ball milling.

The term “sinter” or “sintering” refers a process or technique that involves the application of heat to a material or mixture of materials for densification of said material or mixture of materials, such as powders, such as ceramic or metal powders. Sintering provides heat or high temperatures for powders to bond together into a solid bulk material. Non-exhaustive examples of sintering processes or techniques include spark plasma sintering (SPS), pressureless sintering, hot pressing, microwave sintering, laser sintering, and equivalent techniques. For example, as used herein, hot pressing is an equivalent process to high pressure die casting and pressure welding in which a pressure is applied together with heating. SPS also applies pressure, but uses the pulsed electric current for more rapid and efficient heating.

The term “contiguous” refers to a characterization of two or more materials, regions, or crystallites such that at least one material, region, or crystallite of the two or more contiguous materials, regions, or crystallites has at least one boundary or surface (or any portion(s) thereof) touching or in physical contact with at least one boundary or surface (or any portion(s) thereof) of at least one other material, region, or crystallite of the two or more contiguous materials, regions, or crystallites that are characterized as contiguous. For example, a first region is contiguous with a second region if at least one boundary or surface (or any portion(s) thereof) of the first region is touching or is in physical contact with at least one boundary or surface (or any portion(s) thereof) of the second region.

The term “relative density” refers to a ratio, optionally represented by a corresponding percentage value, of a real measured density of a material (or region thereof) to a theoretical density (i.e. maximum density determined from the crystal structure) of the material (or respective region thereof). A real material may contain pores such that the real density may be lower than a theoretical density of the material. Relative density and porosity (see the response to the next question) can be measured by means such as in water using the Archimedes principle. The term “porosity” refers to a property of a material (or region thereof) that equals 1 minus the relative density ratio or 100% minus the relative density percentage. For example, as used herein, a material having a relative density of 95% is understood to have a porosity of 5%. A high relative density, and low porosity, are generally preferred for a wide variety of applications.

The term “crystallite” refers to a single crystalline volume of a solid material generally characterized by one particular crystal structure throughout said volume. Generally, but not necessarily, a single crystallite has one uniform or homogenous chemical composition throughout the said volume, optionally excluding minority additives or dopant species that may optionally be non-uniformly distributed. A crystallite may be a crystalline grain. Each crystallite in a polycrystalline material may be separated from other crystallites by one or more surfaces, one or more grain boundaries, one or more amorphous regions, one or more areas or volumes having a different chemical composition, one or more areas or volumes having different crystal structure or polymorph or phase, or any combination of these. In some embodiments, a crystallite is a volume contained by one or more surfaces, one or more grain boundaries, one or more amorphous regions, one or more areas or volumes having a different chemical composition, one or more areas or volumes having different crystal structure or polymorph or phase, or any combination of these. Herein, descriptions of crystallite size and average crystallite size refer empirically-derived size characteristics of crystallites based on, determined by, or corresponding to data from any art-known technique or instrument that may be used to determine a crystallite size, such as, but not limited to, x-ray diffraction (XRD) and electron microscopy (SEM and/or TEM). Generally, to the extent not inconsistent with definitions and descriptions herein, the terms grain boundary, surface, crystallite, amorphous, particle, and thin film have meanings recognized by one of skill in the art of materials science.

The term “and/or” is used herein, in the description and in the claims, to refer to a single element alone or any combination of elements from the list in which the term and/or appears. In other words, a listing of two or more elements having the term “and/or” is intended to cover embodiments having any of the individual elements alone or having any combination of the listed elements. For example, the phrase “element A and/or element B” is intended to cover embodiments having element A alone, having element B alone, or having both elements A and B taken together. For example, the phrase “element A, element B, and/or element C” is intended to cover embodiments having element A alone, having element B alone, having element C alone, having elements A and B taken together, having elements A and C taken together, having elements B and C taken together, or having elements A, B, and C taken together.

The term “±” refers to an inclusive range of values, such that “X±Y,” wherein each of X and Y is independently a number, refers to an inclusive range of values selected from the range of X-Y to X+Y.

In an embodiment, a composition or compound of the invention, such as an alloy or precursor to an alloy, is isolated or substantially purified. In an embodiment, an isolated or purified compound is at least partially isolated or substantially purified as would be understood in the art. In an embodiment, a substantially purified composition, compound or formulation of the invention has a chemical purity of 95%, optionally for some applications 99%, optionally for some applications 99.9%, optionally for some applications 99.99%, and optionally for some applications 99.999% pure.

DETAILED DESCRIPTION

In the following description, numerous specific details of the devices, device components and methods of the present invention are set forth in order to provide a thorough explanation of the precise nature of the invention. It will be apparent, however, to those of skill in the art that the invention can be practiced without these specific details.

Disclosed herein is a new class of high-entropy metal/ceramic composite (HEMCC) materials for high temperature applications. HEMCC is a unique and new material that contains a HEA phase and a HEC phase in its microstructure. The HEMCCs combines the high strength of ceramics and high fracture toughness of metals, which enable them as promising materials for next-generation gas turbines, combustion engines, solar power concentrators, thermal protection systems for hypersonic vehicles, plasma-facing materials in nuclear fusion reactors, and structural materials for gas-cooled fast reactors. HEMCCs will survive the operation temperatures over 1000 QC to even 1600 QC, and provide a high strength and fracture toughness at these temperatures in the harsh environments.

Exemplary embodiments of HEMCC materials disclosed herein may include: the composition of HEMCC includes metal elements (e.g., Ti, Zr, Nb, Ta, Hf, Mo, V, W, Cr) and nonmetal elements (e.g., C, B, N, O); the microstructure of HEMCC includes a metal phase and a ceramic phase; the metal phase is a single-phase HEA formed by four or more refractory metal elements from Ti, Zr, Nb, Ta, Hf, Mo, V, W and Cr in equal or near-equal concentrations; the ceramic phase is HEC formed by a single-phase carbide of four or more refractory metal elements (from Ti, Zr, Nb, Ta, Hf, Mo, V, W, etc.), or a single-phase boride of four or more refractory metal elements (from Ti, Zr, Nb, Ta, Hf, Mo, V, W, etc.), in equal or near-equal concentrations and the volume percentage of metal or ceramic phase ranges from 0 to 90%.

Certain aspects of an exemplary synthesis process of HEMCCs is shown in FIG. 1 , which may include four steps: (1) mix the metal powders and mill (e.g., ball mill) to form the precursor for HEA; (2) mix the ceramic powders and mill (e.g., ball mill) to form the precursor for HEC; (3) mix and mill (e.g., ball mill) the mixture of precursors; and (4) sinter the powders into the bulk material with a high relative density of >95% by spark plasma sintering (SPS).

Accurate control of many processing parameters is important for the synthesis of HEMCCs with the optimized microstructures to realize the outstanding mechanical properties at high temperatures. Methods for making a HEMCC material may include, for example, the following embodiments: the starting materials to synthesize the HEMCC are a mixture of metal and ceramic powders; the metal powders are from four or more refractory metal elements from Ti, Zr, Nb, Ta, Hf, Mo, V, W and Cr in equal or near-equal concentrations; the ceramic powders are either four or more binary carbides from TiC, ZrC, NbC, TaC, HfC, MoC, VC and WC, or four or more binary borides from TiB₂, ZrB₂, NbB₂, TaB₂, HfB₂, VB₂, MoB, and WB, in equal or near-equal concentrations; the metal and ceramic powders are mixed with various ratios, in which the ceramic powders are in 0-90% percentage; the ball milling parameters include the speed from 100 to 1000 rpm and the duration of from greater than 0 hours to less than or equal to hours, optionally from 5 to 50 hours; and/or the SPS parameters include the temperature from 1000° C. to 2500° C., optionally 1500° C. to 2500° C., the pressure range of 25 to 500 MPa, optionally 25 to 100 MPa, and a duration selected from the range of 1 to 30 minutes, optionally 5 to 30 minutes.

An exemplary HEMCC material is synthesized using the above process parameters, which contains a HEA phase of TiTaNbZr and a HEC phase of (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C. FIG. 2 shows exemplary scanning electron microscopy (SEM) images of an as-synthesized HEMCC with different volume percentages of HEA and HEC phases, which show the typical microstructures that are very dense (<5% porosity) and have bonded interfaces between the HEA and HEC phases. FIG. 3 shows the density of a HEMCC as a function of the volume percentage of the HEC phase, demonstrating that the density can be tuned (e.g., because the HEC phase has a lower density than the HEA phase), for example, to meet weight requirements of turbine blades. FIG. 4 shows the measured Vickers hardness of a HEMCC as a function of the volume percentage of HEC phase. The hardness generally increases with more HEC phase in this HEMCC, which is in the range of 6 to 19 GPa, for example. FIG. 5 shows the measured bending strength and fracture toughness of a HEMCC as a function of the volume percentage of HEC phase. The bending strength reaches the maximum in the HEMCC with 50% HEC and 50% HEA. The fracture toughness decreases with more HEC phase. Overall, the HEMCC with 50% HEC and 50% HEA combines a high strength and toughness. The relationship between the microstructures of HEMCC and mechanical properties (hardness, strength, and toughness) can aid in designing HEMCCs with the desired mechanical performance for turbine blades.

HEMCCs are materials applicable to applications such as aviation, nuclear energy technology, natural gas power technology, transportation, aircraft engines, automobile engines, electronics, electrical components, next-generation gas turbines, combustion engines, thermal protection systems for hypersonic vehicles, solar power concentrators, plasma-facing materials in nuclear fusion reactors, and structural materials for gas-cooled fast reactors. HEMCCs survive the operation temperatures over 1000 QC to even 1600 QC, for example, and provide a high strength and fracture toughness at these temperatures in harsh environments.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example, patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent, each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.

As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to “a cell” includes a plurality of such cells and equivalents thereof known to those skilled in the art. As well, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably. The expression “of any of claims XX-YY” (wherein XX and YY refer to claim numbers) is intended to provide a multiple dependent claim in the alternative form, and in some embodiments is interchangeable with the expression “as in any one of claims XX-YY.”

When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups, including any structural polytypes or polymorphs of the group members, are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure. When a compound is described herein such that a particular isomer, enantiomer or diastereomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomers and enantiomer of the compound described individual or in any combination. Additionally, unless otherwise specified, all isotopic variants of compounds disclosed herein are intended to be encompassed by the disclosure. For example, it will be understood that any one or more hydrogens in a molecule disclosed can be replaced with deuterium or tritium. Isotopic variants of a molecule are generally useful as standards in assays for the molecule and in chemical and biological research related to the molecule or its use. Methods for making such isotopic variants are known in the art. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently.

Every material, method, device, and formulation described or exemplified herein can be used to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when the composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's invention, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.

As used herein, “comprising” is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

One of ordinary skill in the art will appreciate that starting materials, reagents, synthetic methods, purification methods, and analytical methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. 

1. A high-entropy metal/ceramic composite (“HEMCC”) material comprising: one or more high-entropy metallic alloy (“HEMA”) regions characterized by a HEMA composition, the HEMA composition comprising four or more metal elements; wherein an atomic percent of each of the four or more metal elements of the HEMA composition is within 10% of an atomic percent of each other of the four or more metal elements of the HEMA composition; one or more high-entropy ceramic (“HEC”) regions characterized by a HEC composition, the HEC composition comprising four or more metal elements and one or more nonmetal elements; wherein an atomic percent of each of the four or more metal elements of the HEC composition is within 10% of an atomic percent of each other of the four or more metal elements of the HEC composition; wherein: each HEMA region is free of the HEC composition and each HEC region is free of the HEMA composition; at least one HEMA region is contiguous with at least one HEC region; and the one or more HEMA regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material and/or the one or more HEC regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material.
 2. The material of claim 1, wherein each HEMA region comprises one or more crystallites characterized by the HEMA composition or wherein each HEMA region is independently a crystallite characterized by the HEMA composition.
 3. The material of claim 1, wherein each HEC region comprises one or more crystallites characterized by the HEC composition or wherein each HEC region is independently a crystallite characterized by the HEC composition.
 4. The material of claim 1 comprising two or more HEMA regions and two or more HEC regions; wherein each HEMA region is independently a crystallite characterized by the HEMA composition and each HEC region is independently a crystallite characterized by the HEC composition.
 5. The material of claim 1, wherein each HEMA region and each HEC region independently has a homogeneous composition.
 6. The material of claim 1, wherein the one or more HEMA regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material and the one or more HEC regions are greater than 0 vol. % and less than or equal to 90 vol. % of the HEMCC material
 7. The material of claim 1, wherein a sum volume percent of the one or more HEMA regions and the one or more HEC regions is selected from the range 95 vol. % to 100 vol. %.
 8. (canceled)
 9. The material of claim 1, wherein the HEMA composition is characterized by formula FX1Aa: M_(m1) ¹M_(m2) ²M_(m3) ³M_(m4) ⁴ . . . M_(mi) ^(i),  (FX1Aa); wherein: Σ₁ ^(n)m_(i)=1; i is an integer selected from the range of 1 to n; n is an integer selected from the range of 4 to 10; each of M¹, M², M³, and M⁴ and each M^(i), if present, is one of a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(i), if present, is a different refractory metal element from each other of M¹, M², M³, M⁴ and each M^(i); each mi is independently a relative composition of its respective refractory metal element, each mi independently being equal to or within 10% of 1/n; and the sum of each and every mi is
 1. 10. (canceled)
 11. The material of claim 1, wherein the HEMA composition is characterized by formula FX1Ba, FX1Ca, FX1Da, FX1Ea, or FX1Fa: M_(a1) ¹M_(a2) ²M_(a3) ³M_(a4) ⁴  FX1Ba); M_(b1) ¹M_(b2) ²M_(b3) ³M_(b4) ⁴M_(b5) ⁵  (FX1Ca); M_(c1) ¹M_(c2) ²M_(c3) ³M_(c4) ⁴M_(c5) ⁵M_(c6) ⁶  (FX1Da); M_(d1) ¹M_(d2) ²M_(d3) ³M_(d4) ⁴M_(d5) ⁵M_(d6) ⁶M_(d7) ⁷  (FX1Ea); or M_(e1) ¹M_(e2) ²M_(e3) ³M_(e4) ⁴M_(e5) ⁵M_(e6) ⁶M_(e7) ⁷M_(e8) ⁸  (FX1Fa); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a refractory metal element different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each a is independently a relative composition of its respective refractory metal element, each a independently is equal to 0.25 or within 10% of 0.25, and the sum of each and every a is 1; each b is independently a relative composition of its respective refractory metal element, each b independently is equal to 0.20 or within 10% of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective refractory metal element, each c independently is equal to (⅙) or within 10% of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective refractory metal element, each d independently is equal to ( 1/7) or within 10% of ( 1/7), and the sum of each and every d is 1; and each e is independently a relative composition of its respective refractory metal element, each e independently is equal to 0.125 or within 10% of 0.125, and the sum of each and every e is
 1. 12. The material of claim 1, wherein the HEMA composition is characterized by formula FX2A, FX2B, FX2C FX2D, FX2E, FX2F, FX2G, FX2H, FX2I, FX2J, FX2K, FX2L, or FX2M: Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)  (FX2A); Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)  (FX2B); Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)  (FX2C); W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)  (FX2D); Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25)  (FX2E); Hf_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)  (FX2F); Mo_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)  (FX2G); Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2)  (FX2H); W_(0.2)Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)  (FX2I); Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)W_(1/6)  (FX2J); Mo_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)W_(1/6)  (FX2K); Hf_(1/6)Zr_(1/6)Ti_(1/6)Nb_(1/6)Ta_(1/6)Mo_(1/6)  (FX2L); or Hf_(1/7)Zr_(1/7)Ti_(1/7)Nb_(1/7)Ta_(1/7)Mo_(1/7)W_(1/7)  (FX2M).
 13. The material of claim 1, wherein the HEC composition is characterized by formula FX3A: (M)_(k)(A)_(p)  (FX3A); wherein: each M is four or more refractory metal elements; A is one or more nonmetal elements; and each of k and p is independently 1, 2, 3, 4, or
 5. 14. (canceled)
 15. The material of claim 1, wherein the HEC composition is characterized by formula FX3B: (M_(r1) ¹M_(r2) ²M_(r3) ³M_(r4) ⁴ . . . M_(rj) ^(j))_(k)(A)_(p),Σ₁ ^(u)r_(j)=1  (FX3Bb); wherein: j is an integer selected from the range of 1 to u; u is an integer selected from the range of 4 to 10; each of M¹, M², M³, and M⁴ and each M^(j), if present, is one of a refractory metal element; each of M¹, M², M³, and M⁴ and each M^(j), if present, is a different refractory metal element from each other of M¹, M², M³, M⁴ and each M^(j); each rj is independently a relative composition of its respective refractory metal element, each rj independently is equal to or within 10% of 1/u, and the sum of each and every rj is 1; each of k and p is independently 1, 2, 3, 4 or 5; and A is one or more nonmetal elements.
 16. The material of claim 13, wherein A is C, B, N, O, or a combination of these.
 17. (canceled)
 18. (canceled)
 19. The material of claim 1, wherein the HEC composition is characterized by formula FX3Ca, FX3Fa, FX3Ea, FX3Fa, or FX3Ga: (M_(a1) ¹M_(a2) ²M_(a3) ³M_(a4) ⁴)_(1 or 2)A_(1 or 2)  (FX3Ca); (M_(b1) ¹M_(b2) ²M_(b3) ³M_(b4) ⁴M_(b5) ⁵)_(1 or 2)A_(1 or 2)  (FX3Da); (M_(c1) ¹M_(c2) ²M_(c3) ³M_(c4) ⁴M_(c5) ⁵M_(c6) ⁶)_(1 or 2)A_(1 or 2)  (FX3Ea); (M_(d1) ¹M_(d2) ²M_(d3) ³M_(d4) ⁴M_(d5) ⁵M_(d6) ⁶M_(d7) ⁷)_(1 or 2)A_(1 or 2)  (FX3Fa); or (M_(e1) ¹M_(e2) ²M_(e3) ³M_(e4) ⁴M_(e5) ⁵M_(e6) ⁶M_(e7) ⁷M_(e8) ⁸)_(1 or 2)A_(1 or 2)  (FX3Ga); wherein: each of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸ is a refractory metal element different from each other of M¹, M², M³, M⁴, M⁵, M⁶, M⁷, and M⁸; each a is independently a relative composition of its respective refractory metal element, each a independently is equal to 0.25 or within 10% of 0.25, and the sum of each and every a is 1; each b is independently a relative composition of its respective refractory metal element, each b independently is equal to 0.20 or within 10% of 0.20, and the sum of each and every b is 1; each c is independently a relative composition of its respective refractory metal element, each c independently is equal to (⅙) or within 10% of (⅙), and the sum of each and every c is 1; each d is independently a relative composition of its respective refractory metal element, each d independently is equal to ( 1/7) or within 10% of ( 1/7), and the sum of each and every d is 1; each e is independently a relative composition of its respective refractory metal element, each e independently is equal to 0.125 or within 10% of 0.125, and the sum of each and every e is 1; and A is one or more nonmetal elements.
 20. The material of claim 1, wherein the HEC composition is characterized by formula FX4A, FX4B, FX4C, FX4D, FX4E, FX4F, FX4G, FX4H, FX4I, FX4J, FX4K, FX4L, FX4M, FX4N, FX4Q, FX4P, FX4Q, FX4R, FX4T, FX4Q, FX4V, FX4W, FX4X, FX4Y, or FX4Z: (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))C  (FX4A); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)W_(0.2))C  (FX4B); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Mo_(0.2))C  (FX4C); (Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2))C  (FX4D); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))B₂  (FX4E); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)W_(0.2))B₂  (FX4F); (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Mo_(0.2))B₂  (FX4G); (Hf_(0.2)Zr_(0.2)Mo_(0.2)Nb_(0.2)Ta_(0.2))B₂  (FX4H); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.20)C  (FX4I); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C  (FX4J); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25))C  (FX4K); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C  (FX4L); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C  (FX4M); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.20)N  (FX4N); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N  (FX4O); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25))N  (FX4P); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))N  (FX4Q); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25)W  (FX4R); (Ti_(0.25)Hf_(0.25)Nb_(0.25)Zr_(0.20)B₂  (FX4S); (Hf_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))B₂  (FX4T); (Ti_(0.25)Ta_(0.25)Hf_(0.25)Zr_(0.25))B₂  (FX4U); (Mo_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))B₂  (FX4V); (W_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))B₂  (FX4W); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))C_(x)N_(1-x)  (FX4X); (Ti_(0.25)Ta_(0.25)Nb_(0.25)Zr_(0.25))O₂  (FX4Y); or (Ti_(0.2)Ta_(0.2)Nb_(0.2)Zr_(0.2)Hf_(0.2))O₂  (FX4Z); wherein x is selected from the range of 0 to
 1. 21.-31. (canceled)
 32. A device comprising a high-entropy metal/ceramic composite material according to claim
 1. 33. A method for making a high-entropy metal/ceramic composite (HEMCC) material, the method comprising: mixing one or more metallic precursors and one or more ceramic precursors; wherein: a combined composition of the one or more metallic precursors comprises four or more metal elements; an atomic percent of each of the four or more metal elements in the combined composition of the one or more metallic precursors is within 10% of an atomic percent of each other of the four or more metal elements in the combined composition of the one or more metallic precursors; a combined composition of the one or more ceramic precursors comprises four or more metal elements and one or more nonmetal elements; an atomic percent of each of the four or more metal elements in combined composition of the one or more ceramic precursors is within 10% of an atomic percent of each other of the four or more metal elements in the combined composition of the one or more ceramic precursors; sintering the mixture of one or more metallic precursors and one or more ceramic precursors thereby forming the HEMCC material comprising one or more high-entropy metallic alloy (HEMA) regions and one or more high-entropy ceramic (HEC) regions; wherein the step of sintering is performed under conditions sufficient to form the HEMA from the one or more metallic precursors and the HEC from the one or more ceramic precursors. 34.-43. (canceled)
 44. The device of claim 32, wherein the device is a gas turbine component in the power generation and aviation industries, a coating on structural materials or a fuel cladding component in molten salt reactor (MSR), gas cooled fast reactor (GFR) or very-high temperature reactor (VHTR), or a plasma-facing component for use in the first wall or diverter of a Tokamak nuclear fusion reactor. 